No international roaming (or crazy prices) is one of the big downsides of MVNOs. And no, I'm not interested in buying a local sim card. Roaming is quite affordable these days with the big three and the hassle is not worth it for me.

If you don't need that, I think trying some MVNOs make sense.

Another item is hotspot - typically MVNOs upsell that into a higher tier plan, although presumably not all of them.

That said, if aren't willing to bounce around, prepay months, etc... and are careful about buying new phones on decent promotions, I think the big three are not nearly as much more expensive as the article suggests.

EDIT: I should say, I do have to make phone calls with my existing number, and can't always use wifi or app calling, so I am more inclined to use roaming. I guess for many esim apps work well.